Hemodynamic determinants of prognosis of aortic valve replacement in critical aortic stenosis and advanced congestive heart failure.

Fourteen patients with critical aortic stenosis (valve area 0.4 cm2/m2), a history of advanced congestive heart failure, left ventricular ejection fraction less than 0.45 (mean 0.28 d 0.03) and no other valvular lesions or obstructive coronary artery disease were studied to assess prognosis with aortic valve replacement. Eleven of 14 (79%) survived surgery; 10 of these 11 showed major clinical improvement postoperatively and form group 1. The three patients who died and the patient who did not improve form group 2. Although group 2 had higher preoperative values for aortic valve area and left ventricular end-diastolic volume and lower ejection fraction and cardiac output than group 1, none of these factors alone reliably predicted outcome. The mean systolic gradient was an important predictor of outcome: No patient with a mean systolic gradient 30 mm Hg had a good outcome, irrespective of valve area or other hemodynamic variables. Ejection fraction was plotted against left ventricular wall stress for both groups. For group 1, there was a close linear relation that could be extrapolated back to normal wall stress and normal ejection fraction. This suggested afterload mismatch as a major cause for this group's depressed ejection fraction. In group 2 ejection fraction was lower for any given wall stress, suggesting depressed contractility, rather than afterload mismatch, as the cause of the left ventricular dysfunction. Thus, either afterload mismatch or depressed contractility may result in depressed ejection fraction in patients with aortic stenosis; which one predominates may have major prognostic importance.